ned by characteristics deemed less important.

_Whenever superior rank has been assigned to any selected
characteristic_ by placing divisions based upon it in advance of
divisions based upon other characteristics, _this superiority should be
maintained throughout_.

Example: A partial schedule of Class 80 follows to
illustrate the arrangement of subclasses:

Class 80.--METAL ROLLING.

1. Miscellaneous. | 24. Die rolling--
2. Heating and rolling. | 25. Oscillating rolls.
3. Cutting and rolling. | .. ...
4. Drawing and rolling. | Mills--
5. Annular bodies. | 32. Coiling.
6. Screw threads-- | 33. Work reversing.
7. Concave and roll. | 34. Three or more coacting rolls.
8. Platen rolling-- | 35. Continuous--
9. Dies. | 36. Inclined trains.
10. Rods and wires. | .. ...
11. Tubes-- | 41. Roll cooling and heating.
12. Idle rolls. | 42. Cooling beds.
13. Axial rolling. | 43. Feeding--
14. Segmental rolls. | 44. Tables.
15. Skelping. | .. ...
16. Wheels and disks. | 55. Housings.
17. Reworking. | 56. Roll adjustments--
18. Concave and roll. | 57. Relief devices.
19. Platen and roll. | 58. Rolls--
20. Platen rolling-- | .. ...
21. Disk platens. | 60. Processes--
22. Axial rolling-- | .. ...
23. Pattern rolls. | 66. Flanged bars.

In this schedule the miscellaneous subclass is numbered 1,
then follow three subclasses (2-4) of rolling plus another
function, then four major subclasses (5-16) of rolling,
merely, but applied to blanks of special form producing
special products, then one special subclass (17) based upon
a special class of material treated, then five subclasses
(18-31) specialized in type and mode of operation, then
general types of rolling mills (32-40), then various parts
and accessories (41-59), then processes (60-66). This is
the usual arrangement and is an exhaustive division for the
art of metal rolling. Had there been miscellaneous
subclasses for all combined operations of rolling plus some
other function, a miscellaneous subclass for all mere
rolling machines, either special or general, and a
miscellaneous subclass for all parts and accessories, the
requi